Trans-septal catheter with retention mechanism

ABSTRACT

A medical system for introduction through a septum separating a first heart chamber from a second heart chamber includes a guide catheter with a distal segment and a guide catheter lumen adapted to receive a mapping/ablation catheter. The guide catheter includes a deployable retention mechanism that engages the septum and inhibits advancement or retraction of the guide catheter through the septum. The system also includes an ablation device for delivering ablation energy to tissue. The ablation device is positioned in a heart chamber via the guide catheter lumen.

REFERENCE TO PRIORITY APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/923,320, filed Oct. 24, 2007, which is a divisional of U.S.application Ser. No. 11/399,865, filed Apr. 7, 2006, which is acontinuation of U.S. application Ser. No. 10/152,553, filed May 21,2002, which claims priority to U.S. Provisional Application No.60/292,483, filed May 21, 2001, each of which is incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to trans-septal introducers orguide catheters adapted to introduce an instrument through the septumbetween a left and right heart chamber, and more particularly, thepresent invention relates to a trans-septal guide catheter having aretention mechanism for retaining the distal end of the guide catheterwithin the left heart chamber particularly to enable passagetherethrough of an electrophysiology (EP) catheter.

BACKGROUND OF THE INVENTION

The heart includes a number of pathways through which electrical signalsnecessary for normal, electrical and mechanical synchronous function ofthe upper and lower heart chambers propagate. Tachycardia, that isabnormally rapid rhythms of the heart, is caused by the presence of anarrhythmogenic site or accessory pathway, which bypasses or shortcircuits the nodal pathways in the heart. Tachycardias may becategorized as ventricular tachycardias (VTs) or supraventriculartachycardias (SVTs). The most common SVTs include atrioventricular nodalreentrant tachycardia (AVNRT), Atrioventricular reentrant tachycardia(AVRT), atrial fibrillation (AF), and atrial flutter (AFI). Reentranttachycardias originate in the atria and are typically caused by anaccessory pathway or inappropriate premature return excitation from theventricle through the AV node or left sided accessory pathway.Conditions such as AF and AFI involve either premature excitation fromfocal ectopic sites within the atria or excitations coming throughinter-atrial reentry pathways as well as regions of slow conductionwithin the atria. VTs originate from within the ventricles and havetheir entire circuit contained within the ventricles. These VTs includebundle branch reentrant tachycardia (BBR), right ventricular outflowtract tachycardia (RVOT), and ventricular fibrillation (VF). VTs areoften caused by arrhythmogenic sites associated with a prior myocardialinfarction as well as reentrant pathways between the ventricles. BBRinvolves an inappropriate conduction circuit that uses the right andleft bundle branches. RVOT can be described as a tachycardia originatingfrom the right ventricular outflow tract, which involves ectopictriggering or reentry mechanisms. VF is a life threatening conditionwhere the ventricles entertain a continuous uncoordinated series ofcontractions that cause a cessation of blood flow from the heart. Ifnormal sinus rhythm is not restored, the condition is terminal.

Treatment of both SVTs and VTs may be accomplished by a variety ofapproaches, including drugs, surgery, implantable electricalstimulators, and catheter ablation of cardiac tissue of an effectedpathway. While drugs may be the treatment of choice for many patients,drugs typically only mask the symptoms and do not cure the underlyingcause. Implantable electrical stimulators, e.g., pacemakers, afferentnerve stimulators and cardioverter/defibrillators, which have proven toprovide successful treatment, usually can only correct an arrhythmiaafter it occurs and is successfully detected. Surgical andcatheter-based treatments, in contrast, will actually cure the problemusually by ablating the abnormal arrhythmogenic tissue or accessorypathway responsible for the tachycardia. The catheter-based treatmentsrely on the application of various destructive energy sources to thetarget tissue including direct current electrical energy, radiofrequency (RF) electrical energy, laser energy, ultrasound, microwaves,and the like.

RF ablation protocols have proven to be highly effective in treatment ofmany cardiac arrhythmias while exposing the patient to minimum sideeffects and risks. RF catheter ablation is generally performed after aninitial electrophysiologic (EP) mapping procedure is conducted using anEP mapping catheter to locate the arrhythmogenic sites and accessorypathways. After EP mapping is completed, an RF ablation catheter havinga suitable electrode is introduced to the appropriate heart chamber andmanipulated so that the electrode lies proximate the target tissue. Suchcatheters designed for mapping and ablation, frequently include one ormore cylindrical or band-shaped individual electrodes mounted to thedistal section of the catheter so as to facilitate mapping of a widerarea in less time, or to improve access to target sites for ablation. RFenergy is then applied through the electrode(s) to the cardiac tissue toablate a region of the tissue that forms part of the arrhythmogenic siteor the accessory pathway.

Such mapping and ablation catheters are inserted into a major vein orartery, usually in the neck or groin area, and guided into the chambersof the heart by appropriate manipulation through a venous or arterialroute, respectively. The catheter must have a great deal of flexibilityor steerability to be advanced through the vascular system into achamber of the heart, and the catheter must permit user manipulation ofthe tip even when the catheter body traverses a curved and twistedvascular access pathway. Such catheters must facilitate manipulation ofthe distal tip so that the distal electrode(s) can be positioned andheld against the tissue region to be mapped or ablated.

The arrhythmogenic sites or accessory pathways to be mapped and ablatedfrequently occur within the left atrial wall, particularly aroundpulmonary vein orifices. It is preferable in such cases to introduce aninstrument into the right atrium by a venous route including theinferior vena cava and to advance it through the septum separating theright and left atrium. In one exemplary approach, a guide catheter isinserted in this manner into the right atrium, and instruments areintroduced through the guide catheter lumen that are manipulated fromtheir proximal end and advanced through the septal wall first creating avery small trans-septal perforation, and then enlarging the perforationby dilation or the like. The guide catheter is then advanced over theinstruments or advanced directly through the perforation in the septalwall to locate the guide catheter distal end within the left atrialchamber. The penetrating instruments are retracted from the guidecatheter lumen. The proximal end of the guide catheter is typicallytaped to the patient's body or a support to inhibit retraction back intothe right atrial chamber. The mapping and ablation catheters are theninserted through the guide catheter lumen to locate their distalsegments within the left atrial chamber.

The mapping and ablation procedures are undertaken, the mapping andablation catheters are retracted, and the guide catheter is alsoretracted. The trans-septal perforation tends to shrink as the dilatedmyocardial tissue expands across the perforation.

It is important that the distal segment of the guide catheter insertedthrough the septum remain in place for the entire procedure and not slipback into the right atrium. The guide catheter can be inadvertentlydislodged by movements of the proximal segment emerging from the site ofincision. The dislodgement can require withdrawal of the instruments inuse, jeopardizing their sterility, while delay occurs in reestablishingcatheter position and resumption of the procedure.

In addition, the only way to monitor the location of the distal segmentof the guide catheter is through visualization of a radiopaque marker ofthe guide catheter in regard to recognizable physiologic features of theheart.

It is sometimes necessary that the distal end segment of theelectrophysiology catheter be directed at an acute angle just as itexits the guide catheter lumen to be directed toward certain features ofthe left atrium. Therefore, only a very short distal segment of theguide catheter is extended into the left atrium past the septum so thatthe electrophysiology catheter can be directed to the feature ofinterest. It is more difficult to maintain the distal segment within theleft atrium as the distal segment within the left atrium is shortened.

There is therefore a need for a guide catheter that does not readilyretract through the septum once it has been extended through the septum.

SUMMARY OF THE INVENTION

The present invention is directed to an improved trans-septal guidecatheter that can be passed through a septum from one heart chamber toanother heart chamber and that possesses a retention mechanism formaintaining a distal segment thereof in the other heart chamber. Forexample, the trans-septal guide catheter can be introduced into theright atrium, passed through the atrial septum into the left atrium tolocate a distal segment thereof within the left atrium, and retainedwithin the left atrium so that the distal segment does not readilyretract through the septum into the right atrium.

The trans-septal guide catheter provides access through the septumseparating a right heart chamber from a left heart chamber andpreferably includes an elongated guide catheter body extending betweenguide catheter proximal and distal ends enclosing a guide catheter lumenadapted to provide access into the left heart chamber through a guidecatheter lumen proximal end opening and a guide catheter lumen distalend opening. Retention mechanisms are provided for engaging the septumand inhibiting retraction through the septum of the distal segment ofthe guide catheter extending into the left heart chamber. Thetrans-septal guide catheter particularly enables passage of an EPcatheter through the guide catheter lumen for use in mapping and/orablation of accessory pathways in myocardial tissue of the left atrialheart wall.

In one embodiment, the retention mechanism further includes at least oneflexible, pliant, tine extending outwardly from a tine attachment withthe distal segment of the guide catheter body to a tine free end. Thetine free end is adapted to deflect inward toward the guide catheterbody when restrained during advancement of the guide catheter and toextend further outward from the guide catheter body when restrainedagainst the septal wall when any retraction force is applied to theguide catheter tending to retract the distal segment of the guidecatheter body back into the right heart chamber.

In another embodiment, the retention mechanism includes an inflatableballoon inflated and deflated through an inflation and deflation lumenwithin the guide catheter body extending from a proximal inflation portat the guide catheter proximal end to a balloon inflation port withinthe inflatable balloon. The inflation medium is introduced through theballoon inflation and deflation lumen to inflate the balloon after theballoon is advanced through the septum into the left heart chamber. Theinflated balloon bears against the septal wall and inhibits retractionthrough the septum of the distal segment of the guide catheter extendinginto the left heart chamber.

In still another embodiment, the retention mechanism includes a wirethat is extendable through a wire deployment lumen of the catheter body.A distal wire segment has a non-straight configuration when extended outof the deployment lumen end opening and into engagement with the septalwall of the septum within the left heart chamber that inhibitsretraction through the septum of the distal segment of the guidecatheter extending into the left heart chamber and is straightened whenadvanced through the wire deployment lumen.

The non-straight configuration of the retention wire can include a wirecoil formed of a plurality of wire turns of a coil, e.g., a planar coil,or an acute bend in the wire. The retention wire can be formed of ashape memory alloy to possess superelasticity that enables straighteningof the non-straight configuration within the wire deployment lumen.

The guide catheters of the present invention solve the problem ofmaintaining the distal segment thereof in the heart chamber that thedistal segment is introduced into and enables shortening of the lengthof the distal segment to enable maximal access to features of the heartchamber, particularly the left atrium. The retention mechanisms ensurethat vent ports in the sidewall of the guide catheter body distalsegment are within the heart chamber that the distal segment isintroduced into and are not obstructed by the septum.

The retention mechanisms are preferably located to be deployed or selfdeploy in the heart chamber that the distal segment is introduced intoto inhibit retraction when retraction force is applied to the guidecatheter proximal end drawing the retention mechanism against the septalwall. It will be understood that the deployment mechanisms can bedeployed more proximally to the guide catheter body distal segment tobear against the septal wall when advancement force is applied to theguide catheter proximal end. Slight force can then be applied to holdthe catheter in position without advancing the guide catheter furtherinto the accessed heart chamber. Moreover, it would be possible toduplicate the retention mechanism to deploy a retention mechanism oneither side of the septum.

This summary of the invention and the advantages and features thereofhave been presented here simply to point out some of the ways that theinvention overcomes difficulties presented in the prior art and todistinguish the invention from the prior art and is not intended tooperate in any manner as a limitation on the interpretation of claimsthat are presented initially in the patent application and that areultimately granted.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the invention will becomeapparent from the following description in which the preferredembodiments are disclosed in detail in conjunction with the accompanyingdrawings in which:

FIG. 1 is an overall view of one embodiment of an ablation and/or EPmapping catheter that can be passed through a guide catheter of thepresent invention;

FIG. 2 is a schematic illustration of the introduction of the ablationand/or EP mapping catheter distal section into the left atrium throughthe lumen of a guide catheter extending through an incision orperforation through the septum between the right and left atrium;

FIG. 3 is a simplified schematic illustration of a first embodiment of aguide catheter of the present invention having a deployable retentionmechanism comprising an expandable balloon expanded in the left atriumand drawn against the septal wall in the left atrium to inhibitretraction of the guide catheter distal segment into the right atrium;

FIG. 4 is a cross-section view along lines 4-4 of FIG. 3 depicting theguide catheter lumen and balloon inflation/deflation lumen;

FIG. 5 is a simplified schematic illustration of a second embodiment ofa guide catheter of the present invention having a retention mechanismcomprising a plurality of pliant tines drawn against the septal wall inthe left atrium to inhibit retraction of the guide catheter distalsegment into the right atrium;

FIG. 6 is an end view of the distal segment of the guide catheter ofFIG. 5 depicting the guide catheter lumen and outwardly extending tines;

FIG. 7 is a simplified schematic illustration of a third embodiment of aguide catheter of the present invention having a deployable retentionmechanism comprising an extendable wire that forms a wire coil whenextended from a wire deployment lumen into the left atrium and inhibitsretraction of the guide catheter distal segment into the right atrium;

FIG. 8 is a simplified schematic illustration of the third embodiment ofa guide catheter of the present invention showing the extendable wirethat forms the wire coil when extended into the left atrium retractedinto the wire deployment lumen during introduction or withdrawal of thedistal segment through the septum into or from the left atrium;

FIG. 9 is a simplified schematic illustration of a fourth embodiment ofa guide catheter of the present invention having a deployable retentionmechanism comprising an extendable wire that bends over at an acuteangle when extended from a wire lumen into the left atrium and inhibitsretraction of the guide catheter distal segment into the right atrium;

FIG. 10 is a simplified schematic illustration of the fourth embodimentof a guide catheter of the present invention showing the extendable wirethat bends over when extended into the left atrium retracted into thewire deployment lumen during introduction or withdrawal of the distalsegment through the septum into or from the left atrium;

FIG. 11 is an expanded view of the distal end segment of the extendablewire of FIGS. 9 and 10; and

FIG. 12 is a cross-section view along lines 12-12 of FIGS. 7-10depicting the guide catheter lumen and one embodiment of the extendablewire lumen and extendable wire cross-section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 schematically illustrates an anatomically-conforming, multi-curveablation and/or EP mapping catheter 10 that can be introduced through aguide catheter of the present invention for orienting a distal tipelectrode 12 (or electrodes) with respect to the heart wall for RFablation and/or EP mapping. The multi-curve catheter 10 can incorporatea porous tip and catheter lumen for emitting irrigating fluid around thedistal tip electrode 12, but those features are not illustrated in FIG.1 to simplify illustration. Moreover, the distal segment 32 issimplified in FIG. 1 to show an elongated tubular shaped ablationelectrode 12 and a pair of mapping electrodes 13 and 15 in theillustration of FIG. 1, but the distal segment 32 may include aplurality of ring-shaped electrodes, one or more coil electrode or thelike having other shapes that are presently used or may come into useand including several variations described below in reference to otherfigures including visible or invisible light, infrared, and electricalenergy from or along the distal tip.

The catheter 10 includes a catheter shaft or body 20 and a handle 40.The catheter shaft or body 20 has a shaft axis 24 and extends between adistal end 26 and a proximal end 28 and is separated into a proximalsection 22 and a distal section 30. Catheter body 20 may be of anysuitable diameter and length and may be straight or pre-curved along itslength, but preferably is straight when unrestrained. The distal section30 or the distal segment thereof can be tapered from the diameter of theproximal section 22. Preferably, the catheter body 20 has a uniformoutside diameter of about 0.052 inch (1.32 mm) to 0.1040 inch (2.64 mm)and a length of about 50 cm to 110 cm.

The proximal section 22 has sufficient column strength and is capable ofgood torque transmission to permit controlled placement of the distalsection 30 at a target site in the heart including a selected cardiacvalve or vessel in the manners discussed below. The distal section 30 isdeflectable away from shaft axis 24 and includes a distal segment 32, acurvable proximal segment 36 having a proximal segment length, and abendable intermediate segment 34 having an intermediate segment lengthdisposed between the distal segment 32 and the curvable proximal segment36. The illustrative tip electrode 12 is positioned along the distalsegment 32, preferably extending proximally from the catheter bodydistal end 26 through all or part of the length of the distal segment32. The distal segment 32 can include an elongated ablation electrode 12that may be solid or irrigated and can include one or more proximal ringelectrodes 13, 15 for use in mapping that are either located proximallyas shown or distally from ablation electrode 12. Each electrode isseparately connected to insulated conductors extending proximallythrough the catheter body 20 to terminals of a cable connector in or onthe handle 40 that is connected via a cable to the ablation energysource and/or mapping signal amplifiers. As described further below, athermocouple is also typically included in the distal segment 32 of suchablation catheters, and separately insulated thermocouple conductorsextending proximally through the catheter body 20 to terminals of thecable connector in or on the handle 40 that are coupled via a cable tothe temperature display and ablation energy control apparatus known inthe art.

The handle 40 can take any of the forms known in the art for makingelectrical connections with the conductors within the catheter body 20,for delivering irrigation fluid to an irrigation lumen (if present) ofthe catheter body 20. The handle 40 also includes a mechanism fordeflecting the distal tip section 30 into the shapes provided by thepresent invention. The mechanism can take any form for pulling, pushingand/or twisting the deflection or push/pull wires within the catheterbody 20 as described further below. In the illustrated embodiment, thehandle 40 is attached to the catheter body proximal end 28 and supportsaxially slidable manipulators comprising push-pull rings 44 and 46 and arotatable lateral deflection ring 42 that are coupled to the proximalends of a curve deflection push-pull wire, a knuckle deflectionpush-pull wire, and a lateral deflection wire identified and describedfurther below. The lateral deflection ring 42 can be rotated to impart atorque in a lateral deflection wire coupled thereto to laterally rotatethe distal section 30 with respect to axis 24 within the proximalsection 22.

As shown in FIG. 1, when the push-pull wires are relaxed, the distalsegment 32, the bendable intermediate segment 34, and the curvableproximal segment 36 are aligned with the shaft axis 24 that isreferenced as 0°. The knuckle deflection push-pull wire can be retractedor pulled by sliding ring 46 proximally to impart a small radius bendfrom substantially 0°, wherein the distal and proximal segments 32 and36 are axially aligned, to substantially 180°, whereby the distal andproximal segments 32 and 36 are substantially in side-by-side alignment.The knuckle deflection push-pull wire can be extended or pushed bysliding push-pull ring 46 distally to impart a small radius bend fromsubstantially 0° to about −90°, that is in a bend direction opposite tothe bend direction imparted when the knuckle deflection push-pull wireis retracted or pulled by sliding ring 46 proximally. The intermediatesegment 34 is bent in a bending radius of between 2.0 mm and 7.0 mm, andpreferably less than about 5.0 mm within the bending angle range. Theabrupt knuckle bend angle range can be restricted further by positioningof the slide end stops for the push-pull ring 46 during assembly.

The manipulator push-pull ring 44 can be moved proximally or distally tomove the curve deflection push-pull wire coupled thereto proximally ordistally to form a curve in the proximal segment 36 that is opposed toor in the same direction as the bend imparted in the intermediatesegment 34. The bend or curve of the proximal segment 36 that can beinduced relative to the catheter body axis 24 as depicted in the figurescan be between −90° to +270° relative to the proximal section 22. Thecurvature range of the proximal segment 36 can be restricted further byposition of the slide end stops for the push-pull ring 44 duringassembly.

Many possible co-planar curves induced in the segments of the distalsection 30 in relation to the catheter body axis 24 accomplished byselective movement of the axially slidable manipulator rings 46 and 44coupled to the knuckle deflection push-pull wire 56 and the curvedeflection push-pull wire 54, respectively. The distal end of theknuckle deflection push-pull wire 56 terminates at the junction of theintermediate segment 34 with the distal segment 32, and the curvedeflection push-pull wire 54 terminates at the junction of theintermediate segment 34 with the proximal segment 36. The knuckledeflection push-pull wire 56 and the curve deflection push-pull wire 54extend in parallel with and are radially aligned to the catheter bodyaxis 24 along a common radius extending from the catheter body axis 24through the proximal section 22 and the proximal segment 36. The knuckledeflection push-pull wire 56 is spaced further away from the axis 24than the curve deflection push-pull wire 54 through the proximal section22 and proximal segment 36. The distal section of the knuckle deflectionpush-pull wire 56 traversing the intermediate segment 34 is axiallyaligned with the axis of the curve deflection push-pull wire 54 in theproximal segment 36.

When the ring 42 is rotated clockwise or counterclockwise, the lateraldeflection wire is twisted, causing the junction of the proximal andintermediate segments 36 and 34 to rotate. It will be understood fromthe construction of the lateral deflection wire described below that alateral deflection of the tip segment 32 and the intermediate segment 34in the range of −90° to +90° with respect to catheter body straight axis24 can be achieved by such rotation.

The structure of the catheter body 20 that achieves these angular tipsection deflections and the lateral deflection is illustrated incommonly assigned U.S. Patent Application Serial No. (P-9288.00), filedOct. 10, 2000, in the names of Mark T. Stewart et al. for HEART WALLABLATION/MAPPING CATHETER AND METHOD. The guide catheter of the presentinvention is advantageously employed with this and other ablation and/orEP mapping catheters that are introduced into through the guide catheterlumen that is itself extended from the right atrium through the septumto locate a distal segment of the guide catheter therein as shown inFIG. 2, for example.

FIG. 2 is a schematic illustration of the introduction of the ablationand/or EP mapping catheter distal section into the left atrium throughthe lumen 64 of a guide sheath or catheter 60 extending through anincision or perforation through the septum to locate a guide catheterdistal segment 62 within the left atrium. FIG. 2 illustrates, insimplified form, a sectioned heart 100 and the major vessels bringingvenous blood into the right atrium RA, oxygenated blood into the leftatrium (LA) and the aorta and aortic arch (FIG. 20) receiving oxygenatedblood from the left ventricle (LV). The venous blood is delivered to theRA through the superior vena cava (SVC), the inferior vena cava (IVC)and the coronary sinus (CS) which all open into the right atrium (RA)superior to the annulus of the tricuspid valve leading into the rightventricle. Oxygenated blood from the two lungs is delivered into theleft atrium by the left and right, inferior and superior, pulmonaryveins (LIPV, LSPV, RIPV and RSPV) which are superior to the mitralvalve. The RA and LA are separated by an inter-atrial septum 68, and theRV and LV are separated by a ventricular septum. The tricuspid valve andmitral valve are not shown completely to simplify the figures.

Accessory pathways develop in several parts of the RA and LA that arereached by the catheter 10 to be mapped and/or ablated in accordancewith methods of use thereof. Premature activations that cause atrialfibrillation occur frequently in the LA wall, particularly frompulmonary venous foci around the annular orifices of certain or all ofthe pulmonary veins RIPV, RSPV, LIPV, LSPV shown in FIG. 2. The LA canbe accessed in a retrograde manner through the aorta. However, anotherconvenient approach to the LA is via a puncture or perforation madethrough the inter-atrial septum from the RA. The transseptal guidesheath or catheter 60 depicted in FIG. 2 is inserted through the septum68 via the perforation 66.

The EP mapping/ablation catheter 20 is introduced through the guidecatheter lumen 64, and the handle is manipulated to form the distalsection 30 with about a +90° knuckle bend made in the intermediatesegment and slight positive, neutral or negative curvatures in the rangeof about −45° to +45° in the proximal segment 36 to align the distal tipto locations 2A, 2B or 2C. Continuous lesions can be made around theselected pulmonary valve orifice by successively moving the distalelectrode to the next location and applying RF ablation energy. Themovement can be effected by twisting the distal segment about thecatheter body axis using the deflection wire and manipulator.

These manipulations can require that the length of the guide catheterdistal segment 62 be minimized and can cause inadvertent retraction ofthe distal segment 62 through the perforation 66 in the septal wall 68and into the RA. The guide catheters of the present invention are formedwith a retention mechanism that is deployed to bear against the LA wallaround or alongside the perforation 66. The perforation 66 is firstformed through the septal wall of the septum 68, a distal segment of theguide catheter is advanced into the right heart chamber. In thisparticular case, the guide catheter is advanced through the IVC into theRA and then through the perforation 66 to locate the distal segment inthe LA. Then, the retention mechanism is deployed or self deploys intoengagement with the septum 68 to inhibit retraction of the distalsegment of the guide catheter through the perforation 66 back into RAwhen any retraction force is applied to the guide catheter. In this way,access is provided to introduce instruments or materials into the LA.The preferred use of the guide catheter of the present invention is tointroduce a mapping/ablation EP catheter of the type depicted in FIGS. 1and 2, for example, into the LA. Then, the deployment mechanism iswithdrawn or retracted or overcome by applied retraction force to enablewithdrawal of the guide catheter through the perforation 66.

FIG. 3 is a simplified schematic illustration of a first embodiment of aguide catheter 70 of the present invention having a deployable retentionmechanism comprising an expandable balloon 78 expanded in the LA anddrawn against the septal wall in the LA of the septum 66 to inhibitretraction of the guide catheter distal segment 76 into the RA. FIG. 4is a cross-section view along lines 4-4 of FIG. 3 depicting the guidecatheter lumen 72 and balloon inflation/deflation lumen 82 within theguide catheter body 80.

The inflatable balloon 78 is inflated and deflated through theinflation/deflation lumen 82 that extends within the guide catheter body80 from a proximal inflation port 86 at the guide catheter proximal end74 to a balloon inflation port 84 within the inflatable balloon 78. Theinflation medium (preferably a fluid, e.g., saline or a radiopaquesolution) is introduced through the balloon inflation/deflation lumen 82to inflate the balloon 78 after the deflated balloon 78 is advancedthrough the septum 68 into the LA. The inflated balloon 78 bears againstthe septal wall and resists or inhibits retraction through the septum 66of the distal segment 76 of the guide catheter 70 extending into the LA.The mapping/ablation EP catheter can then be introduced through theguide catheter lumen 72 as depicted in FIG. 2 to map or ablate cardiactissue.

It may be noted that guide catheter 70 may include a second expandableballoon 78 a (shown dashed) that is adapted to be expanded in the RA anddrawn against the septal wall. This is discussed further below.

FIG. 5 illustrates a second embodiment of a guide catheter 90 of thepresent invention having a self deployed retention mechanism thatincludes a plurality of pliant tines 98, 100 drawn against the septum inthe LA to inhibit retraction of the guide catheter distal segment 96through the perforation 66 into the RA. FIG. 6 is an end view of thedistal segment 96 of the guide catheter of FIG. 5 depicting the guidecatheter lumen 92 and outwardly extending tines 98 and 100.

Each such flexible, pliant, tine 98, 100 extends outwardly from a tineattachment 102, 104 with the distal segment of the guide catheter bodyto a respective tine free end 106,108. Preferably, the flexible, pliant,tines 98, 100 extend proximally and outwardly from the respective tineattachments 102, 104 with the guide catheter body 94 at an acute angleto the guide catheter body 94. The tines 98, 100 can be rectangular orcircular in cross-section and can be thinner or thicker than depictedand longer or shorter than depicted. The tines 98, 100 can be formed ofa plastic material, polyurethane or silicone rubber.

The tine free ends 106 and 108 are able to deflect inward toward theguide catheter body 94 by contact against the septum 68 when the guidecatheter 90 is advanced through the perforation 66. The tines 98, 100extend or spread further outward from the guide catheter body 94 againstthe septal wall as shown in FIG. 5 when any retraction force is appliedto the guide catheter 90 tending to retract the distal segment 96 of theguide catheter body back into the RA. While the tines 98, 100 resistbending to extend distally, they can be inverted if sufficientretraction force is applied to the guide catheter body 94 at itsproximal end in order to retract the distal segment 96 through theperforation 66.

It will be understood that more than one tine can be employed arrayedaround the circumference of the catheter body 94. Two additional tines98′ and 100′ are illustrated in broken lines in FIG. 6 to illustratefour tines in this instance. The additional tines 98′, 100′ are formedand function in the same manner as tines 98, 100 as described above.

FIG. 7 illustrates a third embodiment of a guide catheter 110 of thepresent invention having a deployable retention mechanism that includesan extendable wire 112 that forms a wire coil 114 when extended from awire deployment lumen 118 (shown in FIG. 12) into the LA and inhibitsretraction of the guide catheter distal segment 116 into the RA. Thecatheter body 122 encloses a guide catheter lumen 124 (FIG. 12) adaptedto receive a mapping/ablation EP catheter and the wire deployment lumen118 extending between a deployment lumen proximal end opening and adeployment lumen distal end opening in the distal segment 120.

FIG. 8 shows the extendable wire 112 that forms a wire coil 114 whenextended into the LA retracted into the wire lumen 118 duringintroduction into or withdrawal from the RA of the distal segment 116through the perforation 66 in the septum 68.

In use, the elongated retention wire 112 is extended at guide catheterproximal end 126 through the wire deployment lumen 118 to dispose thedistal wire segment 114 within the LA as shown in FIG. 7. The distalwire segment 114 is straightened when advanced through the wiredeployment lumen 118 but forms a non-straight configuration whenextended out of the deployment lumen end opening and into engagementwith the septal wall of the septum 68 within the LA that inhibitsretraction through the septum of the distal segment 120 extending intothe LA. The mapping/ablation EP catheter can then be introduced throughthe guide catheter lumen 124 as depicted in FIG. 2 to map or ablatecardiac tissue. When the procedure is completed, the elongated retentionwire 112 is retracted as shown in FIG. 8 to enable retraction of theguide catheter distal segment 120 back into the RA.

The retention wire 112 and wire lumen 118 can have a circular orrectangular cross-section, and the wire coil 114 can be any desirednon-straight configuration, e.g., a wire coil formed of a plurality ofwire turns wound in a common plane as shown or into any other coilshape. The retention wire 112 can be formed of a shape memory alloy thatpossesses superelasticity that enables straightening of the non-straightconfiguration within the wire deployment lumen 118.

FIGS. 9-11 illustrate a fourth embodiment of a guide catheter 130 of thepresent invention having a deployable retention mechanism that includesa distal section 134 of extendable wire 132. The distal section 134bends over at an acute angle at bend 146 when extended from a wire lumen138 (FIG. 12) into the LA and inhibits retraction of the guide catheterdistal segment 140 into the RA by bearing against the septal wall ofseptum 68. The acute bend 146 in the wire 132 is straightened duringadvancement through the wire deployment lumen 132 as shown in FIG. 10and by the broken lines of FIG. 11.

The retention wire 132 and wire lumen 138 can have a circular orrectangular cross-section. The retention wire 132 can be formed of ashape memory alloy and possesses superelasticity that enablesstraightening of the non-straight configuration within the wiredeployment lumen 138.

Each of the retention wires 112 and 132 can also be formed of anon-conductive plastic material having shape memory of the non-straightconfiguration when released and capable of being straightened totraverse a wire deployment lumen.

It will be seen that the particular embodiments of the guide cathetercan be used to guide ablation/mapping EP catheters like catheter 10 ofFIGS. 1 and 2 or can be used to access the LA from the RA to introduceany other instrument or material into the LA from outside the patient'sbody in performance of any suitable medical procedure. It will also beunderstood that the guide catheters of the present invention can beemployed to access the LV from the RV to introduce any other instrumentor material into the LV from outside the patient's body in performanceof any suitable medical procedure. Moreover, it will be apparent thatsuch a guide catheters of the present invention can be employed toaccess a right heart chamber from a left heart chamber.

Each of the above-described embodiments and alternatives and equivalentsthereof are used in a method of providing access through the septumseparating a right heart chamber from a left heart chamber and deployingthe retention mechanism into engagement with the septum to maintain thedistal segment of the guide catheter extending into the heart chamberaccessed by the perforation in place. The retention mechanisms arepreferably located along the catheter body to be deployed or self deployinto the heart chamber that the distal segment is introduced into toinhibit retraction when retraction force is applied to the guidecatheter proximal end drawing the retention mechanism against the septalwall. It will be understood that the deployment mechanisms can bedeployed more proximally to the guide catheter body distal segment tobear against the septal wall when advancement force is applied to theguide catheter proximal end. Slight force can then be applied to holdthe catheter in position without advancing the guide catheter furtherinto the accessed heart chamber. Moreover, it would be possible toduplicate the retention mechanism to deploy a retention mechanism oneither side of the septum.

For example, referring back to FIG. 3, the balloon 78 and port 84 can belocated along the catheter body to be expanded in the RA. An exemplaryballoon of this nature is shown as balloon 78 a (shown dashed). In oneembodiment, duplicate balloon 78 a and port can be located along thecatheter body to be expanded in the RA along with balloon 78 and port84. Referring to FIGS. 5 and 6, the tines 98, 100 (and 98′, 100′) can belocated along the catheter body to extend outward in the RA and bearagainst the septal wall. Or, a duplicate set of tines can be locatedalong the catheter body to extend outward in the RA along with thedepicted tines 98, 100 (and 98′, 100′). Referring to FIG. 8, the wirecoil 114 can be deployed from the wire deployment lumen 118 from a lumendistal end opening along the catheter body to extend outward in the RAand bear against the septal wall. Or, a duplicate wire coil can bedeployed along the catheter body to extend outward in the RA along withthe depicted wire coil 114. Referring to FIG. 9, the bent wire distalsection 134 can be deployed from the wire deployment lumen 138 from alumen distal end opening along the catheter body to extend outward inthe RA and bear against the septal wall. Or, a duplicate bent wiredistal section can be deployed along the catheter body to extend outwardin the RA along with the depicted bent wire distal section 134.

Although particular embodiments of the invention have been describedherein in some detail, this has been done for the purpose of providing awritten description of the invention in an enabling manner and to form abasis for establishing equivalents to structure and method steps notspecifically described or listed. It is contemplated by the inventorsthat the scope of the limitations of the following claims encompassesthe described embodiments and equivalents thereto now known and cominginto existence during the term of the patent. Thus, it is expected thatvarious changes, alterations, or modifications may be made to theinvention as described herein without departing from the spirit andscope of the invention as defined by the appended claims.

1. A medical device for introduction through a septum separating a firstheart chamber from a second heart chamber, the medical devicecomprising: a guide catheter including an elongated guide catheter bodyextending between guide catheter proximal and distal ends, the guidecatheter body having a distal segment, the guide catheter body enclosinga guide catheter lumen; wherein the retention mechanism includes a firstinflatable balloon and a second inflatable balloon formed about theguide catheter body at the distal segment; wherein the guide catheterbody includes a balloon inflation and deflation lumen positioned withinthe guide catheter body to inflate the first inflatable balloon and thesecond inflatable balloon after the first inflatable balloon is advancedthrough the septum into the one of the first heart chamber and thesecond heart chamber, wherein the inflated first balloon engages theseptum and inhibits retraction of the distal segment of the guidecatheter through the septum, and the inflated second balloon engages theseptum and inhibits advancement of the guide catheter through theseptum; wherein the guide catheter is adapted to perforate the septumand advance the distal segment of the guide catheter into the secondheart chamber; wherein the retention mechanism is deployed intoengagement against the septum within one or both of the first heartchamber and the second heart chamber when one of retraction force andadvancement force is applied to the guide catheter to inhibit movementof the distal segment of the guide catheter through the septum.
 2. Thesystem of claim 1, further comprising an evacuation means to evacuatethe inflation medium to deflate the first balloon and the second balloonand enable advancement or retraction of the distal segment through theseptum between the first heart chamber and the second heart chamber. 3.The system of claim 1 further comprising an ablation device fordelivering ablating energy to tissue, the ablation device being adaptedto be positioned through the guide catheter lumen, the ablation devicecomprising an ablation energy source and an ablation catheter having anablation member coupled to the ablation energy source.
 4. The system ofclaim 3 wherein the ablation member is an ablation electrode.
 5. Thesystem of claim 4 wherein the ablation electrode is selected from thegroup consisting of tubular shaped electrodes, ring-shaped electrodes,and coil electrodes.
 6. The system of claim 3 wherein the ablatingenergy is selected from the group consisting of direct currentelectrical energy, radio frequency electrical energy, laser energy,ultrasound energy, and microwave energy.
 7. A medical system forintroduction through a septum separating a first heart chamber from asecond heart chamber, the medical device comprising: a guide catheterincluding an elongated guide catheter body extending between guidecatheter proximal and distal ends, the guide catheter body having adistal segment, the guide catheter body enclosing a guide catheterlumen; wherein the retention mechanism includes an elongated retentionwire for advancement through a wire deployment lumen of the guidecatheter body, said elongated retention wire having a distal wiresegment that is disposed within the second heart chamber, wherein thedistal wire segment is adapted to be straightened when advanced throughthe wire deployment lumen and to form a non-straight configuration whenextended out of the deployment lumen and into engagement with the septumwithin the second heart chamber, thereby inhibiting retraction of thedistal segment of the guide catheter from the second heart chamber tothe first heart chamber through the septum. wherein the guide catheteris adapted to perforate the septum and advance the distal segment of theguide catheter into the second heart chamber; wherein the retentionmechanism is deployed into engagement against the septum within thesecond heart chamber when retraction force is applied to the guidecatheter to inhibit movement of the distal segment of the guide catheterthrough the septum.
 8. The medical device of claim 7, wherein theelongated retention wire may be retracted within the wire deploymentlumen and disengaged from the septum within the second heart chamber,thereby enabling retraction of the distal segment of the guide catheterinto the first heart chamber through the septum.
 9. The medical deviceof claim 7, wherein the non-straight configuration of the retention wirefurther comprises a wire coil formed of a plurality of wire turns. 10.The medical device of claim 7, wherein the non-straight configuration ofthe retention wire further comprises a wire coil formed of a pluralityof wire turns wound in a common plane.
 11. The medical device of claim7, wherein the non-straight configuration of the retention wire furthercomprises an acute bend in the wire that is straightened duringadvancement through the wire deployment lumen.
 12. The medical device ofclaim 3, wherein the retention wire is formed of a shape memory alloyand possesses superelasticity enabling straightening of the non-straightconfiguration within the wire deployment lumen.